Methane, the primary component of natural gas, is a cheap and abundant feedstock that is costly to transport and requires significant capital expenditures to convert to higher value products (refs. 1, 2; incorporated by reference in their entireties). As a result, natural gas produced in remote locations such as the Bakken Shale is flared, leading to over $18 billion worth of methane being wasted per year (ref 3; incorporated by reference in its entirety). One potential solution is to use biological systems for methane conversion. These systems are predicted to require lower capital expenditures per barrel than traditional gas-to-liquid Technology (refs. 1, 2; incorporated by reference in their entireties).
In nature, methane is aerobically oxidized by bacteria known as methanotrophs, which utilize it for energy production and carbon fixation (ref. 4; incorporated by reference in its entirety). Methane enters the methanotroph metabolic pathway by the action of methane monooxygenases (MMOs), which oxidize methane to methanol (ref. 4; incorporated by reference in its entirety).R—H+O2+2H++2e−→R—OH+H2ONature employs two types of MMOs: soluble MMO (sMMO), which utilizes a diiron cofactor; and particulate MMO (pMMO), which utilizes a dicopper cofactor (FIG. 1) (refs. 5, 6; incorporated by reference in their entireties). A major issue limiting the development of biological gas-to-liquid technology is the inability to express sMMO or pMMO in an industrially relevant host organism (refs. 1, 2; incorporated by reference in their entireties).